Experimental study on supersonic film cooling on the surface of a blunt body in hypersonic flow

Fu, Jia; Yi, Shihe; Wang, Xiaohu; He, Lin; Ge, Yong

doi:10.1088/1674-1056/23/10/104702

Cited by 21 publications

(6 citation statements)

References 23 publications

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“…Tw is the surface temperature during the testing period, and t is the effective test time. The integral term in the equation can be discretized by piecewise linear interpolation method (Fu et al 2014), then it can be converted into the following form:…”

Section: Thin Film Gauges (Tfgs) For Heat Flux Measurementmentioning

confidence: 99%

“…According to the research conclusions of Goldstein et al (1966) and Fu et al (2014), the cooling mass flow ratio (blowing ratio, λ) is an important parameter that influences the film cooling effectiveness, and its definition is as follows:…”

Section: Heat Flux Measurementmentioning

confidence: 99%

“…Meanwhile, he also confirmed that the tangential jet had a higher cooling efficiency than jet with other injection angles. Fu et al (2014) carried out an experiment of air film cooling on a 3D blunt body, and the results showed that increasing the blowing ratio could significantly improve the cooling effectiveness and prolong the cooling length, and a greater amount of cooling gas was required at a bigger angle of attack.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Cooling Efficiency of Hypersonic Optical Window

Zhao

et al. 2022

JAFM

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The cooling effectiveness of optical window influences the imaging quality of hypersonic vehicles. This study focuses on the supersonic film cooling efficiency on the optical window of a blunt cone in hypersonic flow. The experiments were conducted in a gun tunnel equipped with a Mach 8 nozzle providing a total pressure and temperature of 9 MPa and 900 K respectively. Three tangential 2D nozzles with different combinations of slot heights and Mach numbers were designed to detect the film cooling length under different injection pressures. The heat flux on window surface was measured by Thin Film Gauges and the flow field was monitored by schlieren technique. When the jet pressure matched the mainstream, the window was completely cooled, and the minimum mass flow rate was achieved when the slot height was 5mm and the jet Mach number was 2.5. If the pressure ratio of jet continues to increase, the heat flux density could be furtherly reduced, but the cooling efficiency of unit coolant mass flow decreased significantly. The data correlation results showed that the cooling efficiency presented a nonlinear relationship of second order polynomial with (x/Sh)λ -0.8 , and the effective cooling length of film was positively correlated with the cooling mass flow ratio (λ) and slot height of the nozzle. Besides, the increase of jet pressure resulted in thickening the mixing layer, which enhanced the heat insulation effect and reduced the heat flux as a result.

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Section: Thin Film Gauges (Tfgs) For Heat Flux Measurementmentioning

confidence: 99%

Section: Heat Flux Measurementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Cooling Efficiency of Hypersonic Optical Window

Zhao

et al. 2022

JAFM

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“…When operating under high-speed flight conditions, infrared imaging systems often experience a significant reduction in performance due to the impact of aero-optical and aero-thermal radiation effects [1]. To overcome these challenges and maintain detection capability, researchers have explored various approaches, including optical window optimization [2], active cooling [3,4], and back-end algorithm correction [5~7], etc.…”

Section: Introductionmentioning

confidence: 99%

Accurate characterization of full-chain infrared multispectral imaging features under aerodynamic thermal environment

Yang¹,

Zhang²,

Liu³

et al. 2023

Preprint

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The detection performance of infrared imaging systems during high-speed flight is significantly impacted by aero-optical and aero-thermal radiation effects. However, traditional numerical calculations struggle to balance accuracy and efficiency, and there is a lack of a comprehensive model for infrared imaging in an aerodynamic thermal environment. In this study, we propose a calculation method based on Cellular Automata (CA) ray tracing, which allows for parallel calculation of aero-optical and aero-thermal radiation effects by combining optical field transport rules with the cellular space obtained by interpolation under fluid-solid boundary constraints. Using this method, we extend the traditional imaging feature prediction model of the infrared imaging system to obtain an accurate characterization model of the full-chain imaging features adapted to the aerodynamic thermal environment. Finally, we investigate the characteristics of infrared multispectral imaging system in various spectral bands under the influence of aero-optical and aero-thermal radiation effects. With this full-chain imaging model, the key elements of the imaging system under aerodynamic thermal environment can be globally optimized.

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“…Unlike gas turbines, it is extremely difficult to form stable and effective cooling film on the surface of a high speed vehicle. This is mainly because the external high speed flow forms a large normal velocity gradient on the surface of the aircraft and the angle between the incoming flow and the vehicle is constantly changing (Fu et al 2014). Under high speed flying conditions, the flow field around a vehicle contains complex flow structures, such as expansion waves, incident shock waves, shearing layer, boundary layer and separation bubble, etc (Song and Shen 2018).When flow structures change, the flow status and the cooling performance of the cooling film will be influenced, as well.…”

Section: Introductionmentioning

confidence: 99%

Effects of feeding pressures on the flowfield structures of three-dimensional film cooling

Zhao¹,

Yi²,

Mo³

et al. 2022

Fluid Dyn. Res.

Self Cite

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A Mach 2.6 annular supersonic nozzle was designed to protect a hypersonic cone. The annular nozzle is able produce tangential cooling film around the cone. Experiments were carried out in a hypersonic wind tunnel under different cooling film feeding pressures and different attack angles. Temperature-sensitive paint (TSP) was used to measure surface temperature of the cone body; schlieren method was applied to visualize the flow structures. TSP results showed that cooling film can obviously decrease surface heating load, but its efficiency was influenced by the angle of attack (AoA). Schlieren results showed that the shape of upper-lip shock wave is similar to an arc, and the reflected shock wave is more closer to a straight line; both the tilt rate of upper-lip shock wave and the reflected shock wave were increased exponentially with the rise of feeding pressure; a higher feeding pressure resulted in a larger curvature of upper-lip shock wave; compared with reflected shock wave, upper-lip shock wave and shearing layer were more easily affected by the feeding pressure. With higher feeding pressure, incidence point was moved to the further downstream location, and a fitting formula is given to express the relationship between the position of the shock wave incidence point and the feeding pressure.

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Experimental study on supersonic film cooling on the surface of a blunt body in hypersonic flow

Cited by 21 publications

References 23 publications

Experimental Study on Cooling Efficiency of Hypersonic Optical Window

Experimental Study on Cooling Efficiency of Hypersonic Optical Window

Accurate characterization of full-chain infrared multispectral imaging features under aerodynamic thermal environment

Effects of feeding pressures on the flowfield structures of three-dimensional film cooling

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